All single pole single throw switches are digital input devices, as are press to make and press to break switches, basicaly any input that is either on or off.
An input device could be a memory stick and an output device can be a keyboard
Keyboard and a mouse.
Keyboard. Mouse. Trackball. Scanner. Microphone. Digital Fax. Webcam. Number pad. Game pad. Joystick. Digital Pen. And many many more.
keyboard, scanner...
Keyboard & Mouse, most commonly used.